Surface coverings, particularly decorative finished flooring products, often require an underlayment to be installed over a structural wood subfloor or other substrate. Commonly, the underlayment is attached to the substrate by application of an adhesive, nails, screws, staples or any combination thereof. The underlayment serves as a foundation for the application of the surface coverings, and provides a clean, smooth surface upon which to lay the surface coverings. The required thickness of the underlayment is determined by the type of finished flooring product being installed and the amount of deflection in the subfloor.